1. Field of the Invention
The present invention relates to a toner cartridge for use in an image forming apparatus such as a laser beam printer or a multi-functional peripheral, particularly to a toner cartridge for containing toner disposed so as to be exchangeable such as a toner hopper and a toner bottle, and an image forming apparatus using the same.
2. Description of the Related Art
Conventionally, an image forming apparatus using electrophotography such as a copying apparatus, a facsimile apparatus, a printer or a multi functional peripheral having these functions, using a two-component developer is configured to perform a continuous operation of outputting an image by automatically supplying toner to a developing device by a toner supply apparatus using a toner cartridge or the like. Then, in toner shortage, a toner cartridge, a process cartridge, etc. can be easily replaced to supply toner.
Toner containers such as toner cartridges or process cartridges are, when stored in a warehouse or the like, sometimes stacked to face various directions without the stacking directions being controlled. For example, for toner cartridges of a type which discharges toner from one end side of a cartridge main body thereof, when stacked vertically so that a side of a toner discharge port face downward, toners inside the cartridges go down with their own weight as time elapses, therefore, toner density near the toner discharge port becomes high. As a result, toners may aggregate or become an agglomerate to clog the toner discharge port in a serious case.
In the case where the toner cartridge in the above-described state is newly mounted on the image forming apparatus, toner is hard to be discharged from the toner cartridge, and in the worst case, it is possible to be judged as being out of toner even though a large amount of the toner are left in the toner cartridge. Therefore, when newly mounting a toner cartridge, although such a countermeasure that the cartridge is shaken several times before mounting is performed, nevertheless such a problem occurs. Particularly, with a latest toner whose low temperature fixation property is improved for an energy saving measure, preservation stability is deteriorated, and therefore, in a state of being naturally left, there is a tendency that the toner aggregation easily occurs.
In a latest image forming apparatus, reducing the size thereof is required, and therefore, the sizes of a toner container and a developing device are reduced in association therewith, and thus a space of setting those is also made to be smaller. Accordingly, the condition where each of units is closely stuffed up causes a condition where the toner aggregation easily occurs. In mounting the toner cartridge has been stored in the warehouse on the image forming apparatus, even though the user or the like is requested to mount the toner cartridge after shaking it, the user or the like often forgets to do so, so that the toner may not be discharged as a result, and thus causing a trouble such as detection of shortage of toner concentration in a developer or stopping of an image forming apparatus itself. To counter with this problem, for example, Japanese Unexamined Patent Publication JP-A 2000-214667 discloses a developer supplying apparatus in which a part of a conveying spiral of a conveying auger provided in a toner cartridge is cut to reduce pressure of the toner.
However, even in the case of JP-A 2000-214667, there has been a problem that when fluidity of the toner is lost (to be put into a state of loose aggregation) as the toner cartridge has been left for a long time while a toner discharge port is faced downward, in a first toner supply operation after mounted in the image forming apparatus, that is, in rotation of the auger screw, a toner near the toner discharge port is not discharged to the outside of the toner cartridge and as a result, toner which had nowhere to go is fixed as compressed by the pressure of the auger screw, and thus the rotation of the auger screw is locked.